def get_statistic(region, indicator):
    if region == "呼和浩特市":
        hohhot_data = {"总人口": 289.7}
        return hohhot_data.get(indicator, None)
    elif region == "包头市":
        baotou_data = {"GDP": 3000}
        return baotou_data.get(indicator, None)

    return None

print(get_statistic("呼和浩特市", "总人口"))
print(get_statistic("包头市", "GDP"))
print(get_statistic("鄂尔多斯市", "GDP"))
